diff options
Diffstat (limited to 'drivers/cpufreq/cpufreq.c')
| -rw-r--r-- | drivers/cpufreq/cpufreq.c | 69 |
1 files changed, 64 insertions, 5 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 346906a96e8b..6c6121b85a54 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -4,6 +4,9 @@ * Copyright (C) 2001 Russell King * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de> * + * Oct 2005 - Ashok Raj <ashok.raj@intel.com> + * Added handling for CPU hotplug + * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. @@ -567,6 +570,9 @@ static int cpufreq_add_dev (struct sys_device * sys_dev) unsigned long flags; unsigned int j; + if (cpu_is_offline(cpu)) + return 0; + cpufreq_debug_disable_ratelimit(); dprintk("adding CPU %u\n", cpu); @@ -673,7 +679,7 @@ err_out: nomem_out: module_put(cpufreq_driver->owner); - module_out: +module_out: cpufreq_debug_enable_ratelimit(); return ret; } @@ -762,7 +768,6 @@ static int cpufreq_remove_dev (struct sys_device * sys_dev) down(&data->lock); if (cpufreq_driver->target) __cpufreq_governor(data, CPUFREQ_GOV_STOP); - cpufreq_driver->target = NULL; up(&data->lock); kobject_unregister(&data->kobj); @@ -1109,17 +1114,30 @@ int __cpufreq_driver_target(struct cpufreq_policy *policy, unsigned int relation) { int retval = -EINVAL; - lock_cpu_hotplug(); + + /* + * Converted the lock_cpu_hotplug to preempt_disable() + * and preempt_enable(). This is a bit kludgy and relies on how cpu + * hotplug works. All we need is a guarantee that cpu hotplug won't make + * progress on any cpu. Once we do preempt_disable(), this would ensure + * that hotplug threads don't get onto this cpu, thereby delaying + * the cpu remove process. + * + * We removed the lock_cpu_hotplug since we need to call this function + * via cpu hotplug callbacks, which result in locking the cpu hotplug + * thread itself. Agree this is not very clean, cpufreq community + * could improve this if required. - Ashok Raj <ashok.raj@intel.com> + */ + preempt_disable(); dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu, target_freq, relation); if (cpu_online(policy->cpu) && cpufreq_driver->target) retval = cpufreq_driver->target(policy, target_freq, relation); - unlock_cpu_hotplug(); + preempt_enable(); return retval; } EXPORT_SYMBOL_GPL(__cpufreq_driver_target); - int cpufreq_driver_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation) @@ -1406,6 +1424,45 @@ int cpufreq_update_policy(unsigned int cpu) } EXPORT_SYMBOL(cpufreq_update_policy); +static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb, + unsigned long action, void *hcpu) +{ + unsigned int cpu = (unsigned long)hcpu; + struct cpufreq_policy *policy; + struct sys_device *sys_dev; + + sys_dev = get_cpu_sysdev(cpu); + + if (sys_dev) { + switch (action) { + case CPU_ONLINE: + cpufreq_add_dev(sys_dev); + break; + case CPU_DOWN_PREPARE: + /* + * We attempt to put this cpu in lowest frequency + * possible before going down. This will permit + * hardware-managed P-State to switch other related + * threads to min or higher speeds if possible. + */ + policy = cpufreq_cpu_data[cpu]; + if (policy) { + cpufreq_driver_target(policy, policy->min, + CPUFREQ_RELATION_H); + } + break; + case CPU_DEAD: + cpufreq_remove_dev(sys_dev); + break; + } + } + return NOTIFY_OK; +} + +static struct notifier_block cpufreq_cpu_notifier = +{ + .notifier_call = cpufreq_cpu_callback, +}; /********************************************************************* * REGISTER / UNREGISTER CPUFREQ DRIVER * @@ -1466,6 +1523,7 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data) } if (!ret) { + register_cpu_notifier(&cpufreq_cpu_notifier); dprintk("driver %s up and running\n", driver_data->name); cpufreq_debug_enable_ratelimit(); } @@ -1497,6 +1555,7 @@ int cpufreq_unregister_driver(struct cpufreq_driver *driver) dprintk("unregistering driver %s\n", driver->name); sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver); + unregister_cpu_notifier(&cpufreq_cpu_notifier); spin_lock_irqsave(&cpufreq_driver_lock, flags); cpufreq_driver = NULL; |
